1. Field of the Invention
The present invention is related to a method for controlling a display, and more particularly to a method for controlling a RGBW (red, green, blue, white) liquid crystal display.
2. Description of the Prior Art
With the advancement of display panel technologies, liquid crystal display (LCD) panels are widely used in portable devices such as laptops, tablet computers, and smart phones. In general, power consumption of the portable devices should be low so that the portable devices may operate over a long period of time without being charged. However, due to RGB (red, green, blue) LCD panels having low light penetration rate such that only 5% to 10% of light intensity from backlight penetrates panels, energy used for illuminating panels is not fully utilized. Thus pixels should be re-designed to increase light penetration rate so as to utilize energy more efficiently and reduce power consumption of panels.
In contrast, RGBW (red, green, blue, white) LCD panels have higher light penetration rate and lower power consumption because white subpixels having higher light penetration rate are introduced into pixels. However, due to each subpixel (respectively being red, green, blue, white) of RGBW LCD panels occupying a smaller area than that of each subpixel of RGB LCD panels, images displayed on RGBW LCD panels are darker when the images are single colored (pure color), and brightness may be too bright when RGBW LCD panels display all white images. Thus image quality of RGBW LCD panels may be poorer than RGB LCD panels.
Moreover, a color filter of a wide colour gamut LCD panel causes diminution of light penetration rate of the wide colour gamut LCD panel. Thus, the brightness of the wide colour gamut LCD panel is reduced. Further, a multi-wavelength backlight module of the wide colour gamut LCD panel has a poor efficiency for emitting light. Therefore, it is necessary to increase the power of the multi-wavelength backlight module to push the brightness of the panel to a desired brightness. Due to the foresaid factors, the power consumption of the wide colour gamut LCD panel is increased. Accordingly, the battery life of a portable device (e.g. a smart phone, a tablet computer, etc.) having the wide colour gamut LCD panel is shortened, so it would be inconvenient for the user.